In known devices, the peripheral rotating stirrer generally consists of a pair of stirring/scraping blades of helical shape which are fixed diametrically opposite one another on an operating shaft. The helical blades, in addition to stirring the mass of ice-cream in the whipping cylinder, have the function of scraping from the internal wall of the whipping cylinder the layer of mixture which comes to adhere to the wall. This layer of mixture in fact limits the thermal conduction between the mixture and the wall of the whipping chamber which is in a heat-exchange relationship with the associated refrigeration devices and, if not removed, has a particle size which is too large since it grows without undergoing the mechanical action of mixing. Known stirring devices have, however, considerable disadvantages. From the constructional point of view, for the purpose of guaranteeing both the scraping action and the rotation of the stirrer in a perfectly centered position in the cylinder, the arrangement of the helical blades on the stirrer is subject to the strictest tolerances, adherence to which often requires costly rectification treatments. The whole is made considerably more difficult by the great length of the stirrer itself, as a result of which the manufacture of the stirring device is complex and expensive. From the functional point of view, the helical scraping and stirring blades are subject to considerable wear which compromises their functionality, necessitating laborious and complex maintenance interventions. The rubbing of the stirrer against the whipping cylinder moreover causes the undesirable production of metal dust which contaminates the mixture.